Performance improvement

[AryazE]

Reference issue

None

What does this implement/fix?

This improves performance by transforming calculated into a set. As the only use is to check if a value is already calculated, keeping each value once is enough and it is faster to search in a set than a list.

Additional information

This issue was found by DyLin via auto-dylin.

CheckList

• Did you add an unittest for your new example or defect fix?
• Did you add documents for your new example?
• All CIs are green? (You can check it after submitting)

[AtsushiSakai]

LGTM. Thank you!! @AryazE